Example: 2,3,7,8-TCDD (tetradioxin), 2,3,4,7,8-PeCDF
Potential Health Effects in Humans and Animals:
Dioxin is classified by the National Toxicology Program and the World
Health Organization as a known human carcinogen. Dioxin causes increases
in cancers throughout the body and is believed to intensify the effects
of other toxic chemicals. Some workers with high level exposures developed
rare cancers of connective and soft tissues called soft tissue sarcomas.
Dioxin is a known endocrine disrupter. It causes chloracne skin lesions
in humans and is toxic to the nervous system and liver. Based on animal
tests and some evidence in humans, dioxin is also suspected to cause
immune system and thyroid damage, diabetes, endometriosis, testicular
atrophy, lowered testosterone levels and developmental and reproductive
There is broad scientific agreement that dioxins and furans are
among the most toxic chemical compounds known. Furans are chemically
similar to dioxins and generally exert the same types of toxic effects.
Bill Moyers had the highest overall levels of dioxin-like compounds
in his test group. Other much larger studies have found levels similar
to Moyers' in all who have been tested. According to the Environmental
Protection Agency, these exposures are uncomfortably close
to levels that cause health problems in laboratory animals and are
likely to result in an increased risk of cancer in humans
- possibly as many as 1 extra cancer for every 100 people. In January
2001, the National Toxicology Program at the National Institutes
of Health added dioxin to the list of known human carcinogens.
Dioxin is an unwanted byproduct of the manufacture and burning of
products that contain chlorine. The incineration of plastics made
of polyvinyl chloride (PVC) is a major source. So are paper mills
that bleach wood pulp with chlorine. Incinerators across the country
discharge dioxins every day. Even backyard burning of plastic trash
can produce dioxins.
Once dioxin enters the environment, it attaches to dust particles
and can be carried long distances by the wind. From there, dioxin
molecules are absorbed by plants and small organisms, moving up
the food chain to fish, animals and humans.
Most people in the general population are exposed to dioxin through
the food they eat primarily meat, dairy, fish and eggs. People
who consume large amounts of fatty meat and fish probably get the
most, but dioxin is also found at lower levels in grains, fruits
and vegetables. Infants get dioxin in breast milk.
A recent EPA study found dioxin contamination in limestone dust
from cement kilns that burn toxic waste as fuel. According to EPA,
the tainted lime dust is sometimes recycled as fertilizer. Most
states have no restrictions on the use of such fertilizers on food
No data are available on current dioxin releases from specific industries.
In 1999, EPA added dioxin to the list of chemicals that must be
reported on the Toxic Releases Inventory, but no information on
dioxin will be available under TRI until July 2001.
In 1991, EPA began a major reassessment of dioxins health
effects but ten years later - as of March 2001, the EPAs
final report had not been approved. The agency attributes the long
process to the complexities of new scientific findings but
also acknowledges that controversy over dioxins toxicity contributed
to the delay. Industries linked to dioxin contamination have challenged
nearly every aspect of the reassessment. Many people fear that the
long delay will interfere with efforts to impose stricter regulations
on industries and incinerators, although EPA has taken some steps
in the interim to tighten restrictions on dioxin emissions from
paper mills and cement kilns.
For more information on the health
effects of dioxin, visit EPAs dioxin reassessment pages:
Highlights of the reassessment:
Dioxin health effects chapters:
For information on dioxin and cancer, go to the National Toxicology
pdf - http://ehis.niehs.nih.gov/roc/ninth/known/tcdd.pdf
Persistent, Bioaccumulative and Toxic Chemicals dioxin fact
Full list of sources available via e-mail
Dioxin is an unwanted byproduct of the manufacture and burning of products that contain chlorine. The incineration of plastics made of polyvinyl chloride (PVC) is a major source.